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Mechanically triggered drug delivery
Mechanically triggered drug delivery is controlled-release technology in which drug carriers release their payload in response to bodily forces, ultrasound, or magnetic fields, with shear-activated clot-dissolving tPA nanoparticles the best-studied application.
Mechanism of action
Mechanism of action (MOA) is the specific biochemical interaction by which a drug produces its effect, typically via receptors or enzymes; grounded in receptor theory and central to drug development.
Mechanism of action of aspirin
Mechanism of action of aspirin: irreversible acetylation of COX-1 Ser529 and COX-2 Ser516, blocking prostaglandin and thromboxane synthesis; discovered by Vane in 1971; explains analgesic, anti-inflammatory, and antiplatelet effects.
Mechanomyography
Mechanomyography (MMG) is a noninvasive technique that records the low-frequency vibrations and sounds produced by contracting skeletal muscle, serving as the mechanical counterpart of electromyography (EMG) for assessing fatigue, strength, and balance.
Mechanoreceptor
Mechanoreceptors are sensory receptors converting touch, pressure, vibration, and stretch into neural signals. Key cutaneous types include Merkel, Meissner, Pacinian, and Ruffini receptors, with PIEZO2 as the principal mechanotransducer ion channel.
Meckel syndrome
Meckel syndrome (Meckel-Gruber syndrome, dysencephalia splanchnocystica) is a lethal autosomal recessive ciliopathy defined by occipital encephalocele, polycystic kidneys, and polydactyly, fatal before or shortly after birth.
Meckel's diverticulum
Meckel's diverticulum, a true ileal diverticulum from vitelline duct persistence, affects 1–3% of people; ectopic gastric mucosa causes bleeding, obstruction, or diverticulitis, diagnosed by Tc-99m scan and treated by resection.
MECLEES trial
MECLEES (MEdical CLowns EEg Study), NCT05257096, a 2022 randomized trial at Bnai Zion Medical Center, Haifa, showing medical clowns improved EEG quality and cooperation in 100 children aged 1-5 without sedation.
Meclizine
Meclizine (meclozine), a first-generation piperazine antihistamine sold as Antivert, Bonamine, and Dramamine II, treats vertigo and motion sickness; FDA-approved since 1957, dosed 25-100 mg daily, metabolized by CYP2D6, causes drowsiness.
Meconium
Meconium, the newborn's first stool, is a thick greenish-black intestinal discharge of amniotic fluid, bile, and shed cells; passed in utero in 10-25% of births, it can cause meconium aspiration syndrome.
Meconium aspiration syndrome
Meconium aspiration syndrome (MAS): neonatal respiratory distress from inhaling meconium-stained amniotic fluid, affecting 3-5% of MSAF births; treated with ventilation, surfactant, nitric oxide, ECMO; prevented by amnioinfusion, not routine suctioning.
Meconium ileus with perforation
Meconium ileus with perforation (ICD-11 KB87.4) is complicated neonatal ileus where thick meconium obstructs the distal ileum and the bowel ruptures, causing meconium peritonitis; usually linked to cystic fibrosis and treated surgically.
Meconium staining
Meconium passage during delivery (ICD-10 P03.82, ICD-11 KA05.8) is fetal passage of meconium into amniotic fluid during labor, occurring in 12-20% of deliveries; routine intrapartum suctioning is no longer recommended.
Medanta
Medanta, also known as Medanta Hospital, is an Indian multi-specialty hospital network founded in 2009 by cardiac surgeon Dr. Naresh Trehan, with its flagship hospital in Gurugram.
Medazepam
Medazepam, sold as Nobrium, is a long-acting benzodiazepine anxiolytic developed by Roche in 1968, known in Europe as a daytime tranquilizer that relieves anxiety without impairing alertness.
Medial branch block
A medial branch block is a diagnostic injection of local anesthetic onto the nerves supplying spinal facet joints, testing whether those joints are the source of back or neck pain.
Medial collateral ligament
Medial collateral ligament (MCL), or tibial collateral ligament: broad knee ligament from the medial femoral epicondyle to the tibia, the primary restraint to valgus stress and the most commonly injured knee ligament, usually treated non-operatively.
Medial maxillectomy
Medial maxillectomy is a surgical procedure removing the medial maxillary sinus wall, lateral nasal wall, and ethmoid sinuses to treat sinonasal tumors such as inverted papilloma.
Median arcuate ligament syndrome
Median arcuate ligament syndrome (MALS, Dunbar syndrome) is a rare disorder where the diaphragm's median arcuate ligament compresses the celiac artery and celiac plexus, causing postprandial abdominal pain, food fear, and weight loss; treated by surgical ligament release with 70-80% success.
Median lethal dose
Median lethal dose (LD50) is the dose expected to kill 50% of a test animal population, a standard acute toxicity measure in mg/kg. Introduced by Trevan in 1927; the classical OECD 401 test was deleted in 2002 for fewer-animal methods 420, 423, and 425.
Median nerve
Median nerve: terminal branch of the brachial plexus (lateral and medial cords, C5-T1) innervating most forearm flexors, thenar muscles, and the lateral 3.5 digits; compressed in carpal tunnel and pronator syndrome.
Median nerve stimulation
Median nerve stimulation (MNS) is a non-invasive neuromodulation technique that delivers low-frequency electrical pulses over the median nerve at the wrist, used as an awakening therapy in coma for more than 25 years.
Median rhomboid glossitis
Median rhomboid glossitis (MRG), also called central papillary atrophy, is a rare rhomboid red patch on the midline tongue dorsum, usually a chronic Candida albicans infection linked to smoking, dentures, anemia, and diabetes, treated with nystatin when symptomatic.
Median sacral artery
Median sacral artery (arteria sacralis mediana): small unpaired branch of the abdominal aorta just above its bifurcation, descending over L4–L5, sacrum, and coccyx; supplies sacrum, coccyx, and posterior rectum, with common-trunk origin variants relevant to spine and pelvic surgery.
Median sternotomy
A median sternotomy is a surgical incision dividing the breastbone vertically to expose the heart, proposed in 1897 and the standard approach for most cardiac operations since 1957.
Mediastinal arteriovenous malformation
Mediastinal arteriovenous malformation (mediastinal AVM, ORPHA:714709) is an exceedingly rare congenital artery-to-vein connection without capillaries in the chest's mediastinum, prevalence under 1 per million, treated mainly by embolization plus surgery.
Mediastinal lymph node dissection
Mediastinal lymph node dissection (MLND) is the surgical removal of all mediastinal lymph node packets during lung cancer resection, performed for accurate staging and regional disease control.
Mediastinoscopes
Mediastinoscopes: thin, lighted tube-like instruments inserted above the breastbone for mediastinoscopy, introduced by Carlens in 1959; used to biopsy mediastinal lymph nodes, chiefly for lung cancer staging, now often video-assisted (VAMLA).
Mediastinoscopy
Mediastinoscopy is a surgical procedure in which a rigid scope is inserted through a small neck incision to visualize and biopsy mediastinal lymph nodes, chiefly for lung cancer staging.
Mediastinotomy
Mediastinotomy, also known as anterior or parasternal mediastinotomy or the Chamberlain procedure, is a surgical biopsy of mediastinal lymph nodes through a left parasternal incision, reported in 1966.